Let’s start with the digital health element, since I think that’s the more likely feature to make its way into the first generation of a potential smartwatch. According to 9to5Mac’s report, Apple plans to introduce an app called Healthbook in the next version of iOS. This app will reportedly be able to cover all of the activity tracking basics — like calories burned, miles walked and steps taken — and will help users manage weight loss. More interesting, though, is that the app is said to be able to track advanced data like blood pressure, heart rate and hydration and glucose levels.

While the iPhone 5s — with its M7 motion coprocessor — is currently able to measure information like steps taken, measuring data points such as blood pressure and heart rate requires a device that is more likely to be worn on a wrist than placed in a pocket. That’s where the iWatch comes in. 9to5Mac notes that Apple has recently tapped fitness and sensor experts and may be building this functionality into the iWatch. The iWatch could collect the data, and Healthbook couldbe a way to organize and make sense of it. It could also tie in with other apps like Reminders to remind you when to take your medicine, for instance.

As noted, these features are rumored to be included in iOS 8. So if Apple follows its traditional yearly OS release schedule, it means we could also be seeing the iWatch by the end of this year.

A solar-powered smartwatch

In addition to the potential health focus, the New York Times reports that Apple has been looking into solar power and wireless charging for the smartwatch. According to its source, “The watch is expected to have a curved glass screen, and one idea is to add a solar-charging layer to that screen, which would give power to the device in daylight.”

The New York Times points to a number of recently hired engineers at Apple with expertise in battery design and power technology, as well as a recent job listing the company posted for engineers who specialize in solar energy.

The report also mentions that Apple has tested wireless battery charging, similar to the magnetic Qi-based charging pads that Nokia has used in a number of its recent phones. Apple is also said to have tested charging the battery though movement, which is a technique currently employed in other watches on the market. This would mean that movement made while wearing the device could activate a small charging system within it, which could then provide power.

It isn’t clear which, if any, of these charging features will make their way into the iWatch or other Apple products. And unfortunately, the report says that these features are “years from becoming a reality.” A report last month suggested that Apple’s progress on the iWatch was delayed considerably due to battery issues. This goes to show that, in the category of wearables, battery life is arguably one of the most important features to consider.

The way that I see it, users are already accustomed to charging their mobile devices about once a day. But for a smartwatch to really break through, it’ll have to stay charged long enough – and offer enough compelling features — that it’s no longer just a second screen for your smartphone, but an indispensable device in its own right.